Removable ball staked head gimbal assembly

ABSTRACT

In a magnetic head carrying device a method and apparatus for removing a magnetic head carrying arm from a support arm wherein ball stake mounting is used to affix the magnetic head carrying arm to the support arm. A mounting plate is provided having a bevel. Tool blades may be inserted into the bevel to disassemble the ball stake mount.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the arm used to carry a magnetic headin a magnetic disk drive unit. In particular, the invention relates to amethod of removing a ball stake mounted magnetic head from the supportarm.

2. Description of the Prior Art

There has been a continual drive to increase the storage density inmagnetic disk drive units. This has been achieved in part by stackingmagnetic disks in a "pack" all carried within the same disk drive unit.Each side of each disk has its own associated magnetic head used forreading and writing information thereon. Each magnetic head has its ownassociated support arm which positions the head above the disk surface.By moving the arm, the magnetic head is moved between tracks on the disksurface. A servomotor is connected to the opposite end of the supportarm. The magnetic head is moved between tracks by activating theservomotor whereby the support arm pivots and the magnetic head at theopposite tip of the arm is swung between adjacent tracks on the disksurface. A linear actuator may alternatively be used to move a magnetichead. A linear actuator moves the head inward or outward on the diskalong a straight line.

To further increase space savings in the disk drive unit, a singleservomotor typically controls all of the support arms and theirassociated magnetic heads. Thus, all of the support arms are connectedtogether and pivot about the same pivot point. This configuration isidentified as an "E-block" (which refers to the shape formed by theadjacent arms and the servomotor/pivot assembly).

Each magnetic head is connected to the support arm using a mountingmethod known as "ball staking" or "swaging." In ball staking two pieces,a hole in one piece is aligned with a hollow tube which extends from asecond piece. A rounded shape (the "ball") is forced through the hollowtube which causes the tube metal to expand and lock the two piecestogether.

A problem associated with past ball stake mount designs is that there isno economical method to remove a single defective magnetic head from theassembly. Once ball stake mounted, the support structure is verydifficult to disassemble and is easily damaged. Thus, the entire E-blockassembly must typically be replaced if a single magnetic headmalfunctions.

SUMMARY OF THE INVENTION

The present invention provides a method for removing a single ballstaked magnetic head from its associated support arm. Using the presentinvention when a single magnetic head in an E-block assemblymalfunctions, it is only necessary to replace that magnetic head,without discarding the entire E-block assembly.

In the present invention, a bevel is provided between the ball stakedsupport arm and magnetic head. Using this bevel, a removal tool may beinserted such that the ball staking is pried apart. The bevel ispreferably provided by a mounting plate comprising a flat plate with ahollow metal tube which extends from its surface. This plate ispreferably mounted to one of the pieces to be ball staked and ballstaking occurs through the method described above. The tool used toremove the ball staked pieces is preferably a clamping assembly with twoadjustable blades for prying the mount part. The blades may be formed togenerally conform to the bevel. A 20° bevel and corresponding bladeangle is suitable.

The present invention offers significant cost advantages over the priorart because a substantially functional E-block assembly need no longerbe discarded due to a single malfunctioning magnetic head. Replacementof a single head is now possible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a disk pack and its associated E-block assembly.

FIG. 2 is a top view of a magnetic disk and magnetic head arm.

FIG. 3 is a top view of a magnetic head arm.

FIG. 4 is a side view of a magnetic head arm, a magnetic head assemblyand a magnetic disk surface.

FIG. 5 is a side view of a prior art ball staked magnetic head supportarm.

FIG. 6 is a side view of the ball staked magnetic head arm of thepresent invention.

FIG. 7A is a top view of the ball stake mounting plate of the presentinvention.

FIG. 7B is a side view of the ball stake mounting plate of the presentinvention.

FIG. 8 shows a top view of the ball staked support arm of the presentinvention along with a tool used to remove the ball stake mount.

FIG. 9 is a side view of FIG. 9 showing the relationship between theremoval tool and the ball stake mount.

FIG. 10 shows an example of a pliers tool used to remove the ball stakemount

FIG. shows a perspective view of an apparatus used to remove the ballstake mount.

FIG. 12 shows a front elevational view of the apparatus of claim 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A disk drive assembly 10 is shown in FIG. 1 comprising a disk pack 12and E-block assembly 14. Disk pack 12 comprises disks 16 stacked on adrive spindle 18. E-block assembly 14 comprises a servo spindle 20 and aplurality of support arms 22. Each support arm 22 carries one or twoflexure arms 24. Each flexure arm 24 carries a magnetic head assembly26. Each flexure arm 24 is mounted to its corresponding support arm 22by ball stake mount 28. The particular method of mounting ball stakemount 28 is explained below in more detail.

FIG. 2 shows a top view of disk drive assembly 10 of FIG. 1. Servospindle 20 rotates around a pivot axis 30. As servo spindle 20 rotates,magnetic head assembly 26 mounted at the tip of flexure arm 24 swingsthrough arc 32. As disk 16 rotates beneath magnetic head 26, thispivoting motion allows magnetic head assembly 26 to change trackpositions on disk 16. As shown in FIG. 1, as drive spindle 18 rotatesall magnetic head assemblies 26 move in unison.

In FIGS. 3 and 4, a more detailed diagram of flexure arm 24 is shown.Flexure arm 24 is spring loaded, whereby magnetic head assembly 26 isheld in close proximity to disk 16. As disk 16 rotates at high speedabout drive spindle 18, the aerodynamic properties of magnetic headassembly 26 cause assembly 26 to "fly" above the surface of disk 16. Theflying height of magnetic head assembly 26 above disk 16 is a functionof the speed of rotation of disk 16, the aerodynamic lift of magnetichead assembly 26 and the spring tension in flexure arm 24.

FIG. 5 shows a side view of a prior art ball stake mount 34. Prior artball stake mount 34 comprises mounting plate 36, tubular member 38, hole40 in flexure arm 24 and hole 42 in support arm 22. Tubular member 38 ishollow and comprises a malleable material such as a metal. Flexure arm24 is mounted to support arm 22 by placing support arm 22, flexure arm24 and mounting plate 36 as shown in FIG. 5. Mounting plate 36 istypically welded to flexure arm 24. Next, an object with a diameterlarger than the diameter of tubular member 38 is forced through tubularmember 38 such that the material of tubular member 38 is compressedagainst the edges of hole 40 in flexure arm 24 and hole 42 in supportarm 22.

As discussed in the description of the prior art, it is difficult toseparate flexure arm 24 from support arm 22 following the ball stakingprocedure. In fact, when a single magnetic head fails in E-blockassembly 14 the entire E-block assembly 14 often must be discarded andreplaced.

FIG. 6 shows a mount in which the ball staked mount between flexure arm24 and support arm 22 is removable in accordance with the presentinvention. This permits a single magnetic head assembly 26 and itscorresponding flexure arm 24 to be replaced when the magnetic headcarried by that magnetic head assembly 26 malfunctions. The fullyfunctional magnetic heads in the E-block need no longer be wastefullydiscarded. In FIG. 6 ball stake mount 44 of the present invention isshown. Ball stake mount 44 connects support arm 22 with flexure arm 24.FIG. 6 shows a mounting plate 46 sandwiched between support arm 22 andflexure arm 24 and carries tubular member 48 extending through hole 42and support arm 22. During manufacture mounting plate 46 is bonded toflexure arm 24 using, for example, a laser welding procedure. Mountingplate 46 of ball stake mount 44 of the present invention includes abevel 50. Ball stake mount 44 is ball staked in the method as describedabove by forcing an object with a diameter larger than the diameter oftubular member 48 through hole 40 in flexure arm 24, tubular member 48and hole 42 in support arm 22. Bevel 50 provides the means forseparating support arm 22 from flexure arm 24 following ball staking.

FIGS. 7A and 7B show a more detailed view of mounting plate 46 used inthe present invention. Each corner of mounting plate 46 includes bevel50.

FIGS. 8 and 9 show the relationship between ball stake mount 44 andremoval tool 54 of the present invention. Removal tool 54 comprises twoblades which approach bevels 50 from opposing sides. The blades have ablade angle generally conforming to the angle of bevel 50 so that asremoval tool 54 is pressed against bevel 50, tubular member 48 isextracted from hole 42 in support arm 22. Using this removal technique,the defective magnetic head assembly 26 and its associated flexure arm24 may be removed from support arm 22. A new flexure arm 24 carrying afunctional magnetic head assembly 26 may then be attached to the emptysupport arm 22 and ball stake mounted as described above. A suitableblade angle for removal tool 54 has been found to be about 22° andshould generally conform to the angle of bevel 50. Removal tool 54 maybe more conveniently mounted in plier assembly 56 as shown in FIG. 10.Plier assembly 56 ensures that approximately equal forces are applied toboth sides of mounting plate 46 at bevels 50.

FIGS. 11 and 12 also show an apparatus 58 for removing the ball stakemount. A linear slide 60 is mounted to a pedestal 62. Mounted to the topof the slide 60 are housings 64 and 66 which hold the blades 54 in asmall pocket. Running through the housings 64 and 66 is a screw 68 andhandle 70. Screw 68 slides through housing 66 but threads into housing64. As screw 68 is turned, blades 54 are drawn together until the ballstake mount pops free. The slides remain centered by the force ofsprings 72. Total outward movement is controlled by cap screws 74, andtotal inward movement by set screws 76.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. For example, the bevel and removal tool maybe formed in any useful shape or angle. Additionally, the bevel may belocated at any position within the ball stake mount which allowsseparation between the ball stake mounted pieces.

What is claimed is:
 1. A magnetic transducer support comprising:asupport arm including a hole defined in the support arm creating a firstpassageway therethrough; a transducer carrying arm having a hole thereinfor creating a second passageway therethrough; a ball stake connectorfor fixedly mounting the support arm to the transducer carrying arm, theball stake connector including a mounting plate joined to the carryingarm and sandwiched between the carrying arm and the support arm, and atubular member extending from the mounting plate into the firstpassageway for ball staked connection to the support arm; and opposingsurfaces of the support arm and the mounting plate defining toolinsertion gaps between the transducer carrying arm and the mountingplate for use in disengaging the ball stake connector, wherein the toolinsertion gaps are positioned on opposite sides of the mounting plate toreceive a tool and wherein the opposing surfaces receive a separationforce from the tool to cause separation of the ball stake connector andthe support arm.
 2. A magnetic transducer assembly comprising:a flat armcarrying a magnetic transducer head; a second arm having a hole thereinmounted to the first arm; a mounting plate joined to the first arm andsandwiched between the first and second arms, said mounting plate havinga tubular member extending therefrom and into said hole, said tubularmember being ball staked into engagement with said second arm; andopposing surfaces of said mounting plate and said second arm defining aplurality of beveled surfaces for engaging a disassembly tool andreceiving disassembly forces therefrom.
 3. The assembly of claim 2,wherein the mounting plate has four corners, each corner having one ofsaid beveled surfaces.
 4. An apparatus in a magnetic storage systemcomprising:a first arm which carries a magnetic transducer at one endand includes an aperture a the other end; a mounting plate coupled tothe first arm, the mounting plate including a mounting plate face and anelongated hollow member aligned with the first arm aperture; and asecond arm connected to an E-block assembly, the second arm including anaperture and a second arm face, the second arm aperture aligned with thefirst arm aperture and the elongated hollow member, wherein a portion ofthe second arm face is in abutting contact with the mounting plate faceand a portion of the second arm face is spaced apart from the mountingplate face to receive a disassembly tool, and to receive disassemblyforces from the tool for separating the mounting plate and the secondarm.